Wireless Access

Hello Guys!

I would like to collect good practices and configs for this kind of enviroment, which is a really hostile one! 

Also Experience of any of you with this knid of enviroment of what you have done and how did it worked for you?

As general rule i try to educate the client and always tell them from now on you should only buy laptops or devices with abgn do not buy those crappy 1x1 bgn laptops.  And i try to tell them how great 5ghz is.   But the truth is that not always they will listen to you or sometimes they just got a bunch of 2.4ghz 1x1 cards in a really noise 2.4ghz or high interference on 2.4ghz as well.

So well you gotta see what you can do!

As far i can see on the VRD

There are some wepons you can use

1-Noise inmunity( default is 2) = The more noise you got the higher this value you shoudl configure!(i have read many times that is not advisable using this unless a TAC engineer tell you to configure this.

2-Channel Reuse mode:  I really dont understand this too much and if someone can clarify this would be nice :)

I have created this topic because well i do have one implementation with this characteristics.

We have taken the most logic ways to avoid  this like just using 5ghz capable devices, and if not they will get them usb antennas that are capable of 5ghz  if the client is not capable of 5ghz.

Guess there are many channels of 5ghz we can use, and well we will use just 20mhz channel, which bring me one last question

Before i remenber that on the rf profile i just tell it to none on the use of 40mhz channel and that was it, but now in the new code it brings me an error that you need 40mhz channel to use 802.11ac or something like it.   Now i bealive that i have just to turn off these

On the High trhoughput SSID profile disable the very high througput SSID option and 80mhz channel usage

Under rf managment disable very high througput 

After that i can then put the 40mhz channel to none so none of the frequency use it, that way we would have more channels available on 5ghz.

Im asking as i want to correct disable 40mhz channel not just randomly try what i think it is.

Cheers

Carlos

Have you tried enabling DFS channels ? of course you need make sure that the wireless devices can support these channels and there's no weather radars in the area

Well 5ghz last fair was not an issue.   The problem was more likely the 2.4ghz and the laptop that were not 5ghz ready....

the 2.4ghz was horrible... lot of noise and lot of interference.   5ghz was good even without the DFS channels activated.with just the 20mhz channels  on 5ghz everythign was okay on that band.

çLike i said they are buying some usb antennas but he is not sure if he will be able to buy all the ones they need so maybe a few laptops will be on 2.4ghz... and well i woudl like to know what can be done, if we can do asomthing.   As you see i have read on the VRD what can be done but it something ill try for first time, and i would like feedback of people using those features and how it was it? or what else they did ? :)

Have you ever encounter this scenario in which you had to use 2.4ghz and the enviroment was really hostile on it? what did you do???

Cheers

Carlos

I have a customer and at one site in one building they have extreme levels of interference in the 2.4 GHz band.  It is an electronic manufacturing site and the interference is from UV ovens.  The levels of interference is about -60 dBm across the whole spectrum with a very high duty cycle.

They have about 6 of these ovens, and it is fair to say that nothing works in 2.4 GHz band when these things are in use.

We have the production network to only transmit in 5 GHz in this building.  Guest and corp is still provided on 2.4 GHz for convenience, but there is no support or SLA for any device in that building if there are connected on 2.4 GHz.  The customer fully accepts this and understands the reason.

Other locations for this customer have relatively high levels of noise, so I have changed the Interference Immunity to 3.  I've not messed around with the channel re-use parameter though.

Untimately, if your are designing the wireless network you have to make clear your recommendations.  Your recommendations need to be backed up with good data and evidence, which would typically come from a site survey and spectrum analysis.  If they decide to ignore them, at least you have something to go back on.

Even in noisy environments, the Aruba system is second to none for mitigating the effects of interference and in most cases things will still work fine.  In the case above, we gave the customer no choice with respect to 2.4 GHz support in this building.

Nightshade1,

It depends on the type of interference and how much of it there is.  

The first objective is to find and remove the source of interference.  If that is not possible, find out how often it occurs, where it appears and how strong it is.  Some types of interference only occur on certain channels, so you could eliminate those from your regulatory domain profile.

After that, your main objective to to make sure that the source of interference is not between your clients and your access point.  Often, simply by making sure the interference is behind some sort of RF barrier, like a brick wall, you can mitigate some of the interference.  If that fails, sometimes increasing the power on your access point to overcome the interference could actually work.

Beyond that, there is the knobs (1) Interference Immunity and (2) Cell Size Reduction.  They essentially make the access point "deaf" to energy outside of a specific range (I am being very, very general here).  The penalty is the "range".  Your RF will not go as far, and your clients will have to be much closer to the AP as a result.  Could you simply make the AP closer to your clients without enabling any of these?  You should try that first.  The caveat with using either Interference Immunity and Cell Size Reduction is that only the AP ignores the energy outside of a specific range;  the client still has to contend with whatever interference the client sees.  Neither one of those knobs should be changed without TAC, only because they can cause or exacerbate other problems if not used in the proper way.

Hello Collin

I wish i could do a site survey but its not possible...  and if i do it, it will give me false information.

Like i said this is a fair which means that if i go before the fair get started  i wont be able to see the same that i woulld see when the fair starts... i mean when the fair starts there would be a  LOT of stands of different companies with Wireless APS which makes a lot of interference.

We are making sure that all the devices are 5ghz capable but still i need a PLAN B if i need to use 2.4ghz for a device... which i hope we dont have to.

Guess ill call the TAC if i see i need to move Interference inmunity of cell size reduction options, which i hope we dont have to do anythign with that.

Collin

One last question regarding 20mhz and 40mhz channels, as i wish to use 20mhz channels instead 40mhz channels on 5ghz.

Before i remenber that on the rf profile i just tell it to none on the use of 40mhz channel and that was it, but now in the new code it brings me an error that you need 40mhz channel to use 802.11ac or something like it.   Now i bealive that i have just to turn off these

On the High trhoughput SSID profile disable the very high througput SSID option and 80mhz channel usage

Under rf managment disable very high througput 

After that i can then put the 40mhz channel to none so none of the frequency use it, that way we would have more channels available on 5ghz.

Im asking as i want to correct disable 40mhz channel not just randomly try what i think it is.

Cheers

Carlos

Nightshade1,

- There is no "best practice" about avoiding high interference, because different types of interference would require different types of strategies to avoid or mitigate.

- Tell us the specific error you get, when you set 40mz channels to "none" so we can give you information on what to do.

Here is the error

On ARM im changing the Allowed bands for 40MHz channels to none and i get this error:

Error processing command 'rf arm-profile "default" 40MHz-allowed-bands "None"':Error: 40MHz channels must be allowed on 802.11a band to support 80MHz

You should Uncheck 80mhz channel support, when you change "Allowed Bands" to none to avoid that error.

Thank you Collin

Wanted to be sure i didnt need to chance something else!

Cheers

Carlos